Concurrent chemotherapy and external radiation therapy (ConCERT): phase 3 noninferiority randomized clinical trial of cisplatin weekly vs every 3 weeks in locally advanced squamous cell carcinoma of the head and neck.

INTRODUCTION: Concurrent chemoradiotherapy with cisplatin (100 mg/m² every three weeks) is the standard for locally advanced head and neck squamous cell carcinoma (LA-HNSCC), but it is uncertain if weekly cisplatin (40 mg/m²) is non-inferior. METHOD: This open-label, multicentre, phase III non-inferiority trial randomised patients with non-nasopharyngeal LA-HNSCC in a ratio of 1 1 to receive either the standard cisplatin regimen (100 mg/m² every three weeks) or the experimental weekly regimen (40 mg/m²), both with 70 Gy concurrent radiation. The primary endpoint was 2-year locoregional control (LRC) and non-inferiority margin was kept as 10% (-10%). RESULTS: From April 2018-January 2021, 278 patients were enrolled (137 standard and 141 experimental arm); 272 were eligible for final analysis. Median follow-up was 43.9 months. Two-year LRC rates were 61.3% (experimental arm) and 51.1% (standard arm) with an absolute difference of 10.2% (one-sided 95% CI 0.3), within the non-inferiority margin. Hazard ratio was 0.72 (95% CI: 0.50 to 1.05, P = 0.091). Kaplan-Meier analysis also confirmed non-inferiority (absolute difference 10.8%). Median progression-free survival was 17.9 months (standard) and 20.3 months (experimental) (P = 0.204); median overall survival was 22.2 months (standard) and 24.9 months (experimental) (P = 0.501). Grade 3 or higher adverse events occurred more in the standard arm (60.7% vs 44.7%, P = 0.018), as did hospitalisations (36.8% vs 20.3%, P = 0.004). CONCLUSION: Weekly low-dose cisplatin-based chemoradiation is non-inferior to 3-weekly high-dose cisplatin and is associated with lower toxicity and fewer hospitalisations, making it a viable treatment option for non-nasopharyngeal LA-HNSCC.